The present invention relates to a lens array; an LED (Light Emitting Diode) head; an exposure device; an image forming apparatus; and a reading apparatus.
In a conventional image forming apparatus such as a printer and a copier, a conventional reading apparatus such as a scanner and a facsimile, or an image processing apparatus such as a multi-function product, a charge roller charges a surface of a photosensitive drum. Then, an LED (Light Emitting Diode) head as an exposure device exposes the photosensitive drum to form a static latent image thereon. A developing roller with toner attached thereto in a thin layer electro-statically attaches toner to the static latent image, thereby forming a toner image. Afterward, a transfer roller transfers the toner image to a sheet, and a fixing device fixes the toner image, thereby forming an image on the sheet.
In the LED head, a rod lens is provided for collecting light emitted from an LED element on the surface of the photosensitive drum. The rod lens is formed of a glass fiber with ions implanted thereto, so that a refractive index of the glass fiber decreases from a center portion thereof toward a circumferential portion thereof. A plurality of rod lenses is disposed to form a rod lens array, thereby constituting an optical system for forming an upright same-size image of an object in a linear arrangement.
Alternatively, a plurality of micro lenses is disposed to form a rod lens array, thereby constituting an optical system for forming an upright same-size image of an object in a linear arrangement (refer to Patent Reference).
Patent Reference: Japanese Patent Publication No. 2001-249274
A reading apparatus such as a scanner and a facsimile includes a rod lens array for forming an image of an original on a light receiving portion, in which a plurality of light receiving elements is arranged in an array arrangement.
In the conventional image forming apparatus, it is necessary to provide a light blocking plate as a light blocking member for preventing light from a micro lens other than a micro lens having an optical axis matched thereto. The light blocking plate includes a plurality of opening portions. When the micro lenses are arranged with a small interval, it is difficult to form the opening portions in the light blocking plate.
In view of the problems described above, an object of the present invention is to provide a lens array, an LED head, an exposure device, an image forming apparatus, and a reading apparatus capable of easily forming a light blocking member.
Further objects and advantages of the invention will be apparent from the following description of the invention.